Aerial eliminator



Oct. 27, 1931. J, w SPEAKER ET AL 1,828,910

AERIAL ELIMINATOR Filed Jan. 25, 1950 ITLUPFIiOrIS v z/Z/Z/Z M iaeaier yfl/zZ Z/z $615623 x er Patented Get. 27, 1931 UNITED STATES PATENT OFFICE JOHN W. SPEAKER AND ANTON SELSEME-YER, OF XVIIITEFISH BAY, WISCONSIN AERIAL ELIMINATOR The invention in general relates to radio receiving apparatus and more particularly to a method and means for the reduction and elimination of static interference or strays from radio receiving apparatus.

An object of the invention is to provide a device of the character indicated adapted to be conveniently attached to andto form a part of a conventional radio receiving set 19 without change or reorganization thereof.

Another object of the invention is to provide a device of the kind indicated, of simple and inexpensive construction with special adaptation for use in a radio receiving apparatus employing screen-grid vacuum tubes.

The foregoing and such other objects of the invention as will appear hereinafter as the description proceeds, will be more readily understood from a perusal of the following 0 specification, reference being had to the accompanying drawings, in which Figure 1 is a side elevational view of an embodiment of the device.

Fig. 2 is an inverted plan view. Fig. 8 is an enlarged fragmentary vertical sectional view through the device showing the static shunt resistance element in detail.

Fig. 4 is a wiring diagram showing the application of the invention to a conventional type of radio receiving apparatus employing screen-grid vacuum tubes.

In carrying the present invention into practice, advantage is taken of the high amplification factor of the screen-grid vacuum tube which permits the invention to be employed as a unitary device notonly for eliminating static interference but also as a satis factory substitute for an antenna. While no the complete prevention of static interference,

the present method and means provides a radio reproduction.

method yet devised has proved adequate for cal of any circuit which may be employed for With more particular reference to the drawings, 11 designates the device as a unit which preferably comprises a metal plate 12 with which is integrally formed or conductively attached thereto a metal cylinder 13. The plate 12 is of a size sufficient to provide an overhanging edge beyond the periphery of the cylinder 13, said edge having a hole 14 for accommodating the stud 15.to which is fixedly secured a high resistance element 16 which may be of any suitable material, such as carbon. A nut 17 serves to anchor the stud 15 and consequently the resistance element 16 to the underneath side of the, plate 12, while the aperture terminal, 18 of a conductor 19 is secured on the stud 15 by a lock nut 20. A. winding 21 of insulated wire is arranged in the-form of a solenoid on the cylinder 13, oneend 22 of the winding 21 being insulativelya'nchored to the cylinder 13 while the other end 23 is connected to the input of the radio receiving apparatus, as diagrammatically shown in Fig. 4. By inspection of Fig. 4, it is noted that the resistance element 16 is grounded at one end While at its other end a connection is made to the filament ground return of the radio receiving appa ratus.

a When the customary antenna has been replaced by the device 11, electrical oscilla-; tions, received in the inductance or winding 21 which in combination with the metal cylinder 13 serves somewhat as a choke coil, are transmitted through end 23 electrostatically to the radio receiving apparatus, a variable space charge connection being shown in the form of the condenser, 24.

As the details of the radio receiving apparatus, shown by way of example, are con ventional, it will sufiice to explain the functions taking place in the first vacuum tube circuit thereof. On the assumption that the tuned vacuum tube circuits have been placed in resonance with the broadcast wires of the station to be received, it will be found that electrical oscillations will be efliciently received and that the dimunition in energy suffered by the modulated carrier waves in passing through the radio receiving set, by reason of the high resistance shunt element 16, Will not be appreciably'noticed. Static interference or strays, however, will find the non-inductive high resistance shunt element 16, in the present case, to ofier a path of least resistance to ground, since these strays are assumed to be untuned to the circuits resonated only to the carrier waves desired. The device thus acts in the capacity of a filter circuit for the elimination of static interference While performing the functions of an antenna at the same time.

Although an exemplary form of the invention is shown and described it is to be understood that the device is capable of embodying various changes and modifications Without departing from the spirit of the invention or the scope of the appended claim.

A device of the'character described comprising a metallic plate conductively connected to a metallic core in the form of a cylinder, a Winding mounted on said core, a resistance element secured to said plate, said resistance element including a carbon rod extending substantially parallel with said core but spaced therefrom, said plate being conductively connected to said resistance element and having a ground connection, the said Winding having an open circuit and an end connected electromagnetically and electrostatically With the input circuit of a radio receiving apparatus.

In testimony whereof We affix our signatures at Milwaukee County, \Visconsin.

JOHN W. SPEAKER. ANTON SELSEMEYER. 

